Microstructure of vinylidene chloride ethyl acrylate copolymers by one- and two-dimensional NMR spectroscopy

Vinylidene chloride/ethyl acrylate (V/E) copolymers were prepared by photopolymerization using uranyl ion as a photosensitizer at room temperature. Copolymers were characterized by chlorine estimation, gel permeation chromatography, H-1- and C-13-NMR, 2D heteronuclear single quantum correlation (HSQC), and homonuclear 1H-2D double quantum filter correlation spectroscopy (DQF-COSY). Reactivity ratios for the copolymerization of V with E were calculated using the Kelen-Tudos (KT) and the nonlinear error in variables (EVM) methods. The reactivity ratios obtained from the EVM. methods are r(V) = 0.80 +/- 0.15 and r(E) = 0.87 +/- 0.04. The microstructure was calculated in terms of the distribution of V-and E-centered triad sequences from C-13 {H-1}-NMR spectra of the copolymers. 2D HSQC was used to analyze the complex H-1-NMR spectrum and 2D COSY shows the various bond interactions, thus inferring the possible structure of the copolymers. (C) 1998 John Wiley & Sons, Inc.